B1 ~ Revision

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  • Created by: Teresaxox
  • Created on: 11-05-16 21:02

1.1 Diet and Exercise

  • A balanced diet includes everything that is needed to keep the body healthy (TYPES OF FOOD) e.g. Mineral ions, vitamins, carbohydrates,fats and proteins.
  • If someone's diet is unbalanced they can become malnourished. 
  • If you excercise, more energy is used by the body. Excercise increases the METABOLIC RATE which means that the chemicall reactions in cells work faster
  • If the energy (food) taken in is less than the energy used the person will lose mass.
  • The more excercise you do the more food you need. 
  • INHERITED factors also affect the metabolic rate.
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1.2 Weight Problems

  • Eating too much food can lead to someone becoming OVERWEIGHT and OBESE.
  • Long-term obesity can lead to severe health problems such as Type 2 DIABETES.(High Blood Preassure)
  • Can be reduced by eating less carbohydrates and increasing the amount of excercise.
  • Some people are unhealthy because they eat too little (STARVATION). These people might find it hard to walk and suffer from deficiency diseases due to lack of vitamins and minerals.
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1.3 Inheritance, exercise and health

  • As said previously metabolic rate can be INHERITED from your parents. 
  • Two types of cholesterol good and bad.
  • 'GOOD' CHOLESTEROL for your cell membranes and to make vital substances.
  • A small amount of the population inherit 'BAD' CHOLESTEROL which can lead to HEART DISEASE.
  • Foods rich in saturated fats can increase blood cholesterol levels.
  • By exercising regularly a person can increase their metabolic rate and lower high cholesterol levels.
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1.4 Pathogens and disease

  • Pathogens are tiny MICROORGANISMS- ususally BACTERIA or VIRUSES.
  • When bacteria or viruses enter the body they reproduce rapidly which makes us feel ill by producing TOXINS (poisons).
  • Viruses are much smaller than bacteria and reproduce inside of cells. The damage to cells also makes you ill.
  • SEMMELWEISS was the first to realise that infection could be transferred from person to person in a hospital. He told his staff to wash their hands between treating patients.
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1.5 Defence Mechanism

  • The skin prevents pathogens getting into the body.
  • Pathogens are also trapped by mucus and killed by stomach acid.
  • WHITE BLOOD CELLS are part of the IMMUNE SYSTEM. They do 3 things to defend the body.
  • INGEST pathogens (DIGEST and DESTROY)
  • Produce ANTIBODIES to help destroy particular pathogens.
  • Produce ANTITOXINS to get rid of the toxins that pathogens produce.
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1.6 Using drugs to treat disease

  • ANTIBIOTICS kill infective bacteria in the body.
  • Some medicines may relieve the symptoms but not kill the pathogens e.g painkillers.
  • Viruses are difficult to kill because they reproduce in the body cells .
  • Your immune system will usually overcome the ciral pathogen.
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1.7 Growing and investigating bacteria

  • Bacteria can be grown on AGAR JELLY. It must be pure cultures of non-pathogenic (safe) bacteria.
  • Uncontaminated culture of microorganisms can be used to find the effect of of antibiotics on bacteria.
  • Contamination might come from your skin, the air, the soil or the water around you.
  • If the culture becomes contaminated then other bacteria might grow this includes pathogens.

To grow microorganisms in a laboratory you must:

  • Give them a jell containing nutrients- a culture medium (Agar jelly is used).
  • Provide warmth+ oxygen.
  • Keep them incubated at 25°C in school laboratories.

To keep the cultures PURE:

  • Kill all the bacteria on the equipment
  • Prevent microorganisms from air getting into the equipment
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1.8 Changing pathogens

  • Some pathogens particularly viruses can MUTATE(change).
  • Very few people are immune to these changed pathogens so diseases can spread quickly.
  • Diseases that spread within the country result in an EPIDEMIC.
  • Diseases that spread across countries result in a PANDEMIC.
  • Some bacteria have developed resistance to antibiotics by natural selection. This is called MRSA which is the 'super bug'.
  • Mutations of pathogens produce new strains which are resisitant to antibiotics.
  • The resistant bacteria survive and reproduce. This is natural selection.
  • Antibiotics should not be used for mild infections in order to prevent the rate of resisitant strains developing.
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1.9 Immunity

  • Dead or inactive forms of pathogens are used for VACCINES.
  • The White Blood Cells react by producing ANTIBODIES.
  • This makes the person IMMUNE. It prevents further infections because the body responds quickly by producing more antibodies.
  • The antibodies recognise the ANTIGEN (protein shape) on the pathogen.
  • The MMR vaccination (immunisation) is one of the several vaccines. This is given to prevent Measles, mumps and rubella.
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1.10 How do we deal with disease?

  • Get vaccinated to prevent serious diseases.This protects individuals as well as society.
  • Diseases such as measles can lead to long term damage to the body, such as deafness and occasionally death.
  • Some vaccines cause side effects which may be mild or serious.
  • Overuse of antibiotics can lead to the development of of new strains or bacteria.
  • Doctors do not prescribe medicines for mild infections such as sore throats. 
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